2015 OASDI Trustees Report

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IV. ACTUARIAL ESTIMATES
This chapter presents actuarial estimates of the future financial condition of the Social Security program. These estimates show the income, cost, and asset reserves or unfunded obligation of the OASI and DI Trust Funds: (1) in dollars over the 10‑year short-range period; and (2) as a percentage of taxable payroll, as a percentage of gross domestic product, and in present-value dollars over the 75‑year long-range period. In addition, the chapter discusses a variety of measures of the adequacy of current program financing. This report distinguishes between: (1) the cost (obligations) of the program, which includes all future benefits scheduled under current law; and (2) expenditures (disbursements), which include actual payments for the past plus only the portion of projected program cost that would be payable with the financing provisions in current law.
This chapter presents the estimates and measures of trust fund financial adequacy for the short-range period (2015‑24) first, followed by estimates and measures of actuarial status for the long-range period (2015‑89). Summary measures are also provided for trust fund status over the infinite horizon. As described in chapter II of this report, these estimates depend upon a broad set of demographic, economic, and programmatic factors. This chapter presents estimates under three sets of assumptions to show a wide range of possible outcomes, because assumptions related to these factors are subject to uncertainty. The intermediate set of assumptions, designated as alternative II, reflects the Trustees’ best estimate of future experience; the low-cost alternative I is significantly more optimistic and the high-cost alternative III is significantly more pessimistic for the trust funds’ future financial outlook. The tables of this report show the intermediate estimates first, followed by the low-cost and high-cost estimates. Chapter V describes these three sets of assumptions, along with the actuarial methods used to produce the estimates. Appendix D and appendix E present two additional methods to illustrate the uncertainty of the projections. Appendix D presents sensitivity analyses of the effects of variation in individual factors and appendix E presents probability distributions generated by a stochastic model.
A. SHORT-RANGE ESTIMATES
The Trustees consider the trust funds to be fully solvent if the funds can pay scheduled benefits in full on a timely basis. A standard method of assessing solvency is the “trust fund ratio,” which is the reserves in a fund at the beginning of a year (which do not include advance tax transfers) expressed as a percentage of the cost during the year. The trust fund ratio represents the proportion of a year’s cost which the reserves available at the beginning of that year can cover. The Trustees assume that a trust fund ratio of 100 percent of annual program cost provides a reasonable “contingency reserve.” Maintaining a reasonable contingency reserve is important because the trust funds do not have borrowing authority. After reserves are depleted, the trust funds would be unable to pay benefits in full on a timely basis if annual revenue were less than annual cost. Unexpected events, such as severe economic recessions, can quickly deplete reserves. In such cases, a reasonable contingency reserve can maintain the ability to pay scheduled benefits while giving lawmakers time to address possible changes to the program.
The short-range test of financial adequacy applies to the OASI and DI Trust Funds individually and combined on a theoretical basis. If the estimated trust fund ratio is at least 100 percent at the beginning of the projection period, the test requires that it remain at or above 100 percent throughout the 10-year period. If the ratio is initially less than 100 percent, then it must reach at least 100 percent within 5 years (without reserve depletion at any time during this period) and then remain at or above 100 percent throughout the remainder of the 10-year period. This test is applied using the estimates based on the intermediate assumptions. If either trust fund fails this test, then program solvency in the next 10 years is in question, and lawmakers should take prompt action to improve short-range financial adequacy.
1. Operations of the OASI Trust Fund
This subsection presents estimates, based on the assumptions described in chapter V, of the operations and financial status of the OASI Trust Fund for the period 2015-24. These estimates assume that there are no changes in the statutory provisions and regulations under which the OASDI program currently operates.1
Table IV.A1 shows these estimates, which indicate that the asset reserves of the OASI Trust Fund continue to increase through 2021 under the intermediate assumptions, throughout the next 10 years under the low-cost assumptions, and through 2016 under the high-cost assumptions. However, trust fund ratios decline throughout the 10-year period under all three sets of assumptions. Based on the intermediate assumptions, the reserves of the OASI Trust Fund continue to exceed 100 percent of annual cost by a large amount through the end of 2024. Consequently, the OASI Trust Fund satisfies the test of short-range financial adequacy by a wide margin. Table IV.A1 also indicates that the OASI Trust Fund would satisfy the short-range test even under the high-cost assumptions. See figure IV.A1 for an illustration of these results.
Table IV.A1.—Operations of the OASI Trust Fund, Calendar Years 2010-24 1 
GF
reim-
burse-
ments2
Taxa-
tion of
bene-fits3
Trust
fund
ratio 4

1
Appendix A presents a detailed description of the components of income and cost, along with complete historical values.

2
Includes reimbursements from the General Fund of the Treasury to the OASI Trust Fund for: (1) the cost of noncontributory wage credits for military service before 1957; (2) the cost of benefits to certain uninsured persons who attained age 72 before 1968; (3) the cost of payroll tax credits provided to employees in 1984 and self-employed persons in 1984-89 by Public Law 98-21; (4) the cost in 2009-17 of excluding certain self-employment earnings from SECA taxes under Public Law 110-246; and (5) payroll tax revenue forgone under the provisions of Public Laws 111-147, 111-312, 112-78, and 112-96.

3
Revenue from taxation of benefits is the amount that would be assessed on benefit amounts scheduled in the law.

4
The “Trust fund ratio” column represents reserves at the beginning of a year (which are identical to reserves at the end of the prior year shown in the “Amount at end of year” column) as a percentage of cost for the year.

5
Between -$50 million and $50 million.
Note: Totals do not necessarily equal the sums of rounded components.
 

The estimated income shown in table IV.A1 increases annually under each set of assumptions throughout the short-range projection period. The estimated increases in income reflect increases in estimated OASDI taxable earnings and growth in interest earnings on the invested reserves in the trust fund. Employment increases in every year through 2024 for all three alternatives: the number of persons with taxable earnings increases on the basis of alternatives I, II, and III from 166 million during calendar year 2014 to about 188 million, 184 million, and 179 million, respectively, in 2024. The total annual amount of taxable earnings increases in every year through 2024 for each alternative. Total earnings increase from $6,163 billion in 2014 to $12,253 billion, $10,512 billion, and $8,962 billion in 2024, on the basis of alternatives I, II, and III, respectively. These increases in taxable earnings are due primarily to: (1) projected increases in employment levels as the working age population increases; (2) trend increases in average earnings in covered employment (reflecting both real growth and price inflation); (3) increases in the contribution and benefit base under the automatic-adjustment provisions; and (4) growth in employment and average earnings, temporarily higher than trend, as the economy continues to recover from the severe economic downturn that began in late 2007.
Interest earnings generally contribute to the overall projected increase in trust fund income during this period. Despite the projected growth in OASI Trust Fund reserves, annual interest earnings decline slightly in the early projection years under all three sets of assumptions due to historically low interest rates assumed for newly-issued bonds. Thereafter, interest income increases under the intermediate and low-cost assumptions due to the net effects of higher reserve levels and the patterns of projected interest rates. Under the high-cost assumptions, declining reserves cause interest income to continue to decrease throughout the short-range period. Although interest earnings generally increase over the short-range period, interest declines as a share of total OASI Trust Fund income. By 2024, OASI interest income is about 9 percent of total trust fund income under the intermediate assumptions, as compared to 12 percent in 2014.
Rising OASI cost during 2015-24 reflects automatic benefit increases as well as the upward trend in the number of beneficiaries and in the average monthly earnings underlying benefits. The growth in the number of beneficiaries since 2009 and the expected future growth result both from the increase in the aged population and from the increase in the proportion of the population that is eligible for benefits.
The Treasury invests OASI income in financial securities, generally special public-debt obligations of the U.S. Government. The revenue used to make these purchases flows to the General Fund of the Treasury. The trust fund earns interest on these securities, and the Treasury invests maturing securities in new securities if not immediately needed to pay program costs. Program expenditures require the redemption of trust fund securities, generally prior to maturity, to cover the payments made by the General Fund of the Treasury on behalf of the trust fund.
2. Operations of the DI Trust Fund
Table IV.A2 shows the estimated operations and financial status of the DI Trust Fund during calendar years 2015-24 under the three sets of assumptions, together with values for actual experience during 2010-14. Non-interest income increases steadily after 2014 under each alternative, due to most of the same factors described previously for the OASI Trust Fund.  DI cost grows at a slower rate than DI income, but remains greater than DI income. As a result, after having reached a maximum in 2008, DI Trust Fund reserves continue to decrease after 2014 under each alternative. Under the intermediate assumptions, reserves continue to decline until their projected depletion in the fourth quarter of 2016. Under the high-cost assumptions, DI reserves decline steadily until depletion in the third quarter of 2016. Under both the intermediate and high-cost assumptions, reserves are projected to remain depleted through 2024.
Under the low-cost assumptions, reserves are projected to become depleted in the fourth quarter of 2017, but this status would not be permanent. Following reserve depletion in 2017, scheduled DI benefits could not be paid in full and on time for several years. However, non-interest income would become higher than cost in 2021, and by mid-2023 all scheduled DI benefits could be paid in full, including amounts that were not fully payable during the temporary period of reserve depletion. In this low-cost scenario, DI Trust Fund reserves are projected to be positive by mid-2023 and increasing, reaching 5 percent of annual cost at the beginning of 2024.
Taxa-
tion of
bene-fits3

1
The DI Trust Fund becomes depleted in the fourth quarter of 2016 and the third quarter of 2016 under the intermediate and high-cost assumptions, respectively, and remains so through 2024. Under the low-cost assumptions, reserves would be depleted in the fourth quarter of 2017 through early 2023. For any period during which reserves would be depleted, scheduled benefits could not be paid in full on a timely basis, income from taxing benefits would be less than would apply to scheduled benefits, and interest on trust fund reserves would be negligible. Appendix A presents a detailed description of the components of income and cost, along with complete historical values.

2
Includes reimbursements from the General Fund of the Treasury to the DI Trust Fund for: (1) the cost of noncontributory wage credits for military service before 1957; (2) the cost of payroll tax credits provided to employees in 1984 and self-employed persons in 1984-89 by Public Law 98-21; (3) the cost in 2009-17 of excluding certain self-employment earnings from SECA taxes under Public Law 110-246; and (4) payroll tax revenue forgone under the provisions of Public Laws 111-147, 111-312, 112-78, and 112-96.

3
Revenue from taxation of benefits is the amount that would be assessed on benefit amounts scheduled in the law.

4
The “Trust fund ratio” column represents reserves at the beginning of a year (which are identical to reserves at the end of the prior year shown in the “Amount at end of year” column) as a percentage of cost for the year.

5
While the fund is depleted, values under current law would reflect permissible expenditures only, which are inconsistent with the cost of scheduled benefits shown in this table.

6
Between -$50 million and $50 million.

Note: Totals do not necessarily equal the sums of rounded components.
In the future, DI cost increases in part due to increases in average benefit levels resulting from: (1) automatic benefit increases and (2) projected increases in the amounts of average monthly earnings on which benefits are based. The number of DI beneficiaries in current-payment status increases but at a slower rate during the short-range projection period than over the past 20 years.
At the beginning of calendar year 2014, the reserves of the DI Trust Fund represented 62 percent of annual cost. During 2014, DI cost exceeded income, and the trust fund ratio for the beginning of 2015 decreased to about 40 percent. Under the intermediate assumptions, cost exceeds total income throughout the short-range projection period. The projected cost in excess of income results in the estimated depletion of the DI Trust Fund reserves in the fourth quarter of 2016.
Because the reserves of the DI Trust Fund at the beginning of 2015 were less than the estimated annual cost for 2015, and they are projected to remain below annual cost throughout the short-range period, the DI Trust Fund fails the Trustees’ short-range test of financial adequacy under all three alternatives.
3. Operations of the Combined OASI and DI Trust Funds
Table IV.A3 shows the estimated operations and status of the theoretical combined OASI and DI Trust Funds for calendar years 2015-24 under the three alternatives, together with actual experience in 2010‑14. Income and cost for the OASI Trust Fund represent over 80 percent of the corresponding amounts for the combined OASI and DI Trust Funds. Therefore, based on the relative strength of the OASI Trust Fund over the next 10 years, the combined OASI and DI Trust Funds would have sufficient financial resources to pay all scheduled benefits through the end of the short-range period, although it is important to note that under current law, one trust fund cannot share financial resources with another trust fund. In addition, the combined OASI and DI Trust Funds would satisfy the short-range test of financial adequacy under the intermediate and low-cost assumptions. However, under the high-cost assumptions, reserves are projected to drop to about 95 percent of annual cost by the end of 2024, and hence the combined funds would not satisfy the short-range test of financial adequacy.
Table IV.A3.—Operations of the Combined OASI and DI Trust Funds,
Calendar Years 2010-241 
GF
reim-
burse-
ments2
Taxa-
tion of
bene-fits3
Trust
fund
ratio 4